JPS641524B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a state change monitoring device suitable for application to, for example, a blast furnace (molten ore furnace) in a steel factory. The present invention relates to a state change monitoring device that monitors state changes by converting them into stereoscopic images.

Generally, during iron making work in a blast furnace, a conveyor 1 is used to collect coke and
After ore is charged into the hopper 2a and limestone is charged into the hopper 2b, coke, ore and limestone are alternately charged into the furnace interior 5 from these hoppers 2a and 2b via the upper bell 3 and lower bell 4. A blower blows blast air into the furnace interior 5 from the lower tuyere 6. The blast air used is one that has been heated in advance in a hot air stove 7. The hot air stove 7 burns gas for a certain period of time and stores heat in the grate bricks 8 inside the furnace. Next, a blower sends cold air to exchange heat and make hot air. A portion of the hot air is mixed with cold air to maintain the specified temperature. In this case, it is desirable that the pressure and flow rate of the hot air be constant.

By the way, the coke inside the furnace 5 burns and produces CO
Or it becomes CO ₂ gas, which melts the ore and reduces iron oxide, while also reducing Mn, Si, and other impurities in the ore. Then, Mn, Si, etc. are mixed into the separated molten iron along with a certain amount of carbon to form pig iron, which is stored in the hearth 9. When the molten pig iron is sufficiently accumulated in the hearth 9, the tap hole 10 is opened and the molten pig iron is poured into a waiting molten pig transport vehicle, and then transported to a mixed pig iron furnace or a caster.

On the other hand, due to the characteristics of the blast furnace's melting action, the gas emitted from the top of the furnace still contains a large amount of flammable CO gas, H ₂ , and carbohydrates, which are used as fuel and a power source. 11 is a gas collection pipe, 12 is a cooling plate, 13
is the slag outlet.

By the way, in the above-mentioned blast furnace ironmaking work,
There are various factors that can cause furnace conditions to deteriorate during furnace operation. That is,
The charge loaded into the furnace interior 5 undergoes very complex physical and chemical changes, such as the distribution and descending state of the charge, the temperature inside the furnace due to the suitability of the blower, and the blowing pressure. Modulations in the gas distribution state caused by the height of the air flow mix and influence.

However, there is currently no means to monitor changes in these physical and chemical conditions inside the furnace 5, and the only way to monitor these physical and chemical state changes is to monitor the furnace surface pressure, surface temperature, etc. using thermocouples, radiation thermometers, etc. It was merely a matter of measuring and monitoring. Temperature radiation inside the furnace 5 (thermal radiation)
The light emitted by the furnace is absorbed and scattered before it reaches the furnace surface and cannot be observed, and laser light cannot pass through the inside of the furnace either.

Therefore, in the past, the only way to estimate changes in the state inside the furnace 5 and to detect and deal with malfunctions in the furnace beforehand was to rely on the skill and experience of engineers.

The present invention has been made in view of the above circumstances, and uses energy transmission development to continuously monitor the gas distribution inside the furnace, the distribution of the charge, its descending state, etc., without disturbing the internal situation of the furnace. The object of the present invention is to provide a state change monitoring device that enables the operation of the furnace and also detects malfunctions in the furnace during operation in order to stabilize the operation.

An embodiment of the present invention will be described below with reference to the drawings. In FIG. 2, reference numeral 20 indicates the outer shape of an imaginary furnace, and a radiation scanner 2 that generates radiation at high speed across a certain cross section of the furnace 20.
1 and a radiation detector group 22 are arranged. This radiation scanner 21 swings a radiation beam across the furnace cross section in a fan shape, and a radiation detector group 22 detects the radiation intensity after passing through the radiation beam. Therefore, upon completion of one radiation scan, one-dimensional projection data of a fan-shaped cross section as shown in FIG. 2B is obtained on the radiation detector group 22. In the same figure, B is the radiation intensity, and θ is the detection angle (scanning angle). This one-dimensional projection data is then stored in a storage unit such as a computer (not shown) and used for data processing.

Next, FIG. 3 is the same in that a radiation scanner 21 and a radiation detector group 22 are arranged across the furnace 20, but in particular in FIG. Each radiation scanner 21 constitutes a scanner group 21', and each radiation scanner 21 individually emits a radiation beam in a fan shape, thereby allowing the radiation detector group 22 to obtain projection data from multiple directions. . However, each radiation detector has one direction defined by a collimator, or radiation scanning is controlled so that radiation does not enter one detector from more than one direction at the same time. shall be.

Next, a detailed explanation will be given of how the above-described apparatus is used to determine the state of change inside the blast furnace. now,
Assuming that the radiation intensity that entered the blast furnace interior 20 after scanning with the radiation scanner 21 is I ₀ , and the radiation intensity after passing through the blast furnace is assumed to be of single energy, the radiation intensity is as shown in equation (1). become.

I=I ₀ exp (− 〓 ⁱ μ _i・Δx _i ) ...(1) Here, μ _i is the absorption coefficient of the material along the radiation path, and Δx _i is the absorption coefficient of the material along the path of the radiation. This is the value corresponding to the length. The absorption coefficient μ _i is a function of density and varies greatly depending on the substance. It also shows different values depending on the energy of the radiation.

For simplicity, in equation (1), Δx _i = Δx (constant)
Then, when logarithmic transformation is performed, ln(I ₀ /I)=Δx・〓 ⁱ Δμ _i ...(2). The right side is the sum of the absorption coefficients μ _i . That is, (2)
The absorption coefficient μ _i is continuously restored by obtaining projections as shown in the equation from multiple directions in a short time. This allows us to know the internal state of the cross section of the furnace and its changes. The absorption coefficient μ _i is restored by combining the radiation detection group 22 and an electronic computer.

This method of using a computer to reconstruct cross-sectional images is called computerized tomography (Computed Tomography (hereinafter referred to as CT) in English), and is used in medical equipment to perform cross-sectional cross-sectional imaging of the head and whole body. It is used for imaging. These devices depict the location of a lesion very clearly as a two-dimensional image, and are highly effective in determining treatment strategies. CT is characterized by its high density resolution. That is, CT can of course distinguish between liquids, air, solids, etc., and can also identify and separate objects whose radiation absorption coefficients differ only slightly.

Therefore, this device can detect the blast furnace by arranging the radiation scanner 21 (or the radiation detection group 21') and the radiation detector group 22 in multiple stages facing each other from the hearth 9 to the top of the blast furnace as shown in FIG. Changes in internal physical and chemical conditions can be reconstructed as images continuously over time throughout the reactor. Therefore, the state change monitoring device can constantly monitor the distribution and descending state of charges such as coke, ore, and limestone. Abnormal monitoring of the rate of descent of the charge is one of the important aspects of furnace instrumentation. The most common abnormality is a phenomenon called ``tanatsuri'' (the filling in the furnace no longer descends), which tends to occur when high-temperature air is blown into large blast furnaces. In this case, the cane will be lowered by reducing the air flow rate to lower the pressure in the lower part of the furnace.

Furthermore, with this device, based on the same principle, it is also possible to grasp changes in the gas distribution state caused by changes in the blowing pressure.

By the way, equation (2) can be replaced with the following equation.

l _o (I ₀ /I) = Δx 〓 ⁱ μ _i /ρ _i・ρ _i ...(3) Here, ρ _i is the density of the material along the radiation path. Also, μ _i /ρ _i is called the mass absorption coefficient of a substance, and as is already known, for radiation of the same energy, if you exclude substances with large atomic numbers such as lead, most of the The value is almost constant for all substances. Therefore, μ _i /
If ρ _i =α, equation (3) can be changed to I _o (I ₀ /I)=Δx·α 〓 ⁱ ρ _i ……(4). The right side of this equation is the sum of the densities of the materials. In this case, as described above, the density ρ _i of the substance can be continuously restored by performing projections based on equation (4) from multiple directions in a short time.

In order to accurately obtain ρ _i , the following methods can also be considered. First, calculate μ _i from equation (2), and use that value to determine what kind of substance is present at that point. This is because the charge inside the blast furnace is usually limited. Then,
Since the mass absorption coefficient μ _i /ρ _i of the substance is known from experimental values, etc., by substituting it into equation (3) and finding it again, it is possible to find ρ _i more accurately than equation (4). Therefore, with the above configuration, not only can the density distribution and changes in the blast furnace be observed continuously in three dimensions, but also the temperature distribution in the blast furnace can be visualized by visualizing the density changes due to temperature of solids, liquids, or gases. You can also ask for

As described in detail above, according to the present invention, the energy generator and the detector group are arranged in multiple stages facing each other across the container into which the charge is loaded, and the radiation energy transmission phenomenon and the electronic computer are utilized. Since the structure is designed to project the physical and chemical changes of the charge inside the container, it is possible to continuously monitor the distribution of the charge and its descending state, as well as the temperature distribution and gas distribution state inside the container, without disturbing the conditions inside the container. can be projected and monitored. Therefore, this device can detect, for example, malfunctions in the furnace during blast furnace operation from projection data, without relying on the skills and experience of engineers like in the past, and when combined with automatic control technology, it can dramatically improve operations. can be stabilized.

In addition, since the state inside the furnace is imaged every moment, it is possible to accurately investigate the mechanism of physical and chemical changes in the contents inside the furnace and various factors that cause poor furnace conditions during operation.

It goes without saying that the application of this device is not limited to blast furnaces. In short, it can be widely applied to cases where the inside of a device undergoes extremely complex physical and chemical changes due to high temperatures, etc., and these changes cannot be directly observed from the outside.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the general structure of a conventional blast furnace main body, and FIG. 2 is a view showing the basic configuration of a state change monitoring device according to the present invention. A diagram showing the relationship between
is a diagram of one-dimensional projection data indicating the radiation intensity detected by a group of radiation detectors, Figure 3 is a diagram explaining another example of the device of the present invention, and Figure 4 is a specific example of the device of the present invention applied to a blast furnace. FIG. 5... Furnace interior, 9... Hearth, 20... Blast furnace, 2
1...Radiation scanner (radiation generator), 21'...
Radiation scanner group, 22... Radiation detector group.

Claims (1)

[Claims] 1. In cases where the loaded material undergoes chemical and physical state changes due to the high temperature inside the container, at least one part of the outer periphery of the container that generates enough energy such as radiation to pass through the loaded material inside the container. One energy generator is provided, and a group of detectors for detecting the energy generated from the energy generator is arranged on the other outer periphery of the container, and a plurality of energy generators and detector groups are arranged in the longitudinal direction of the container. The energy transmitted from the energy generator through the inside of the vessel and detected by the detector group is processed by an electronic computer to reconstruct the image to obtain a cross-sectional image. A 3D image of the inside of the furnace was created from the cross-sectional image, and this 3D image was displayed to monitor changes in the physical and chemical state of the charges inside the furnace, and to detect malfunctions in the furnace before they occurred. A state change monitoring device characterized by: